Different strokes for different folks!While many liked the split 50/50 cocking effort on our original bolt design the “Dynamic Close Bolt”, we understand that some prefer a bolt which requires less effort to close, so we are now offering our newly designed “Dynamic Open Bolt”, which biases more of the energy upon opening the bolt, therefore requiring less effort to close!Don’t worry! The only difference is the bolt body and cocking piece, all of the internals and bolt heads are interchangeable!